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1.
Sci Total Environ ; 730: 138888, 2020 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-32402961

RESUMO

Eastern China has been facing severe winter haze pollution due mainly to secondary aerosol. Existing studies have suggested that stagnant weather or fast chemical production led to frequent haze in this region. However, few works focus on the linkage between secondary production of sulfate, nitrate, and ammonium (SNA) and synoptic conditions, and their joint contribution to PM2.5. In this study, by combining in-situ measurements on meteorology and aerosol chemical composition at three main cities together with a regional model with improved diagnose scheme, we investigated the chemical formation and accumulation of main secondary composition, i.e. SNA under typical synoptic conditions. It is indicated that SNA did play a vital role in haze pollution across eastern China, contributing more than 40% to PM2.5 mass concentration. As most fast developing region, the Yangtze River Delta (YRD) was slightly polluted during stable weather with local chemical production accounting for 61% SNA pollution. While under the influence of cold front, the pollution was aggravated and advection transport became the predominant contributive process (85%). Nevertheless, the chemical production of SNA was notably enhanced due to the uplift of air pollutant and elevated humidity ahead of the cold front, which then facilitated the heterogeneous and aqueous-phase oxidation of precursors. We also found the substantial difference in the phase equilibrium of nitrate over the land surface and ocean due to changes in temperature, ammonia availability and dry deposition. This study highlights the close link between synoptic weather and chemical production, and the resultant vertical and spatial heterogeneity of pollution.

2.
Proc Natl Acad Sci U S A ; 116(49): 24463-24469, 2019 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-31740599

RESUMO

From 2013 to 2017, with the implementation of the toughest-ever clean air policy in China, significant declines in fine particle (PM2.5) concentrations occurred nationwide. Here we estimate the drivers of the improved PM2.5 air quality and the associated health benefits in China from 2013 to 2017 based on a measure-specific integrated evaluation approach, which combines a bottom-up emission inventory, a chemical transport model, and epidemiological exposure-response functions. The estimated national population-weighted annual mean PM2.5 concentrations decreased from 61.8 (95%CI: 53.3-70.0) to 42.0 µg/m3 (95% CI: 35.7-48.6) in 5 y, with dominant contributions from anthropogenic emission abatements. Although interannual meteorological variations could significantly alter PM2.5 concentrations, the corresponding effects on the 5-y trends were relatively small. The measure-by-measure evaluation indicated that strengthening industrial emission standards (power plants and emission-intensive industrial sectors), upgrades on industrial boilers, phasing out outdated industrial capacities, and promoting clean fuels in the residential sector were major effective measures in reducing PM2.5 pollution and health burdens. These measures were estimated to contribute to 6.6- (95% CI: 5.9-7.1), 4.4- (95% CI: 3.8-4.9), 2.8- (95% CI: 2.5-3.0), and 2.2- (95% CI: 2.0-2.5) µg/m3 declines in the national PM2.5 concentration in 2017, respectively, and further reduced PM2.5-attributable excess deaths by 0.37 million (95% CI: 0.35-0.39), or 92% of the total avoided deaths. Our study confirms the effectiveness of China's recent clean air actions, and the measure-by-measure evaluation provides insights into future clean air policy making in China and in other developing and polluting countries.

3.
Artigo em Inglês | MEDLINE | ID: mdl-31429970

RESUMO

BACKGROUND: The 2012 European Society of Intensive Care Medicine (ESICM) guidelines provided a clear definition of feeding intolerance (FI). The study aimed to investigate the association between FI based on the current ESICM definition and clinical outcome and to further explore the effect of the duration of FI on mortality. METHODS: Adult patients from 14 general intensive care units (ICUs) with an expected ICU stay ≥24 hours were prospectively studied. Based on FI duration in the first week of admission to the ICU, FI was categorized as 7-day persistent feeding tolerance (FT), delayed FT, delayed FI, and 7-day persistent FI. The primary outcomes were 28-day and 60-day all-cause mortality. RESULTS: Of 499 patients, the prevalence of 3-day and 7-day persistent FI was 39.2% (n = 196) and 25.4% (n = 106), respectively. The patients with 3-day FT had lower risk of 28-day and 60-day mortality rates and higher prevalence in ventilator weaning and vasoactive medication on the seventh day of ICU admission than those with 3-day FI. Three-day FI remained an independent predictor for 60-day mortality. In a subgroup analysis including 418 patients with 7-day survival, compared with those with 7-day persistent FT, the odds ratios of 60-day mortality were 1.67, 1.97, and 2.62 in the patients with delayed FT, delayed FI, and 7-day persistent FI, respectively. CONCLUSION: FI was associated with increased mortality and longer duration of mechanical ventilation and vasoactive support. Prolonged or relapsing FI represented an incremental risk of adverse outcomes in critically ill patients.

4.
Oxid Med Cell Longev ; 2019: 5768953, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31249646

RESUMO

Aging is a complex life process, and a unified view is that metabolism plays key roles in all biological processes. Here, we determined the lipidomic profile of Caenorhabditis elegans (C. elegans) using ultraperformance liquid chromatography high-resolution mass spectrometry (UPLC-HRMS). Using a nontargeted approach, we detected approximately 3000 species. Analysis of the lipid metabolic profiles at young adult and ten-day-old ages among wild-type N2, glp-1 defective mutant, and double mutant daf-16;glp-1 uncovered significant age-related differences in the total amount of phosphatidylcholines (PC), sphingomyelins (SM), ceramides (Cer), diglycerides (DG), and triglycerides (TG). In addition, the age-associated lipid profiles were characterized by ratio of polyunsaturated (PUFA) over monounsaturated (MUFA) lipid species. Lipid metabolism modulation plays an important role in reproduction-regulated aging; to identify the variations of lipid metabolites during germ line loss-induced longevity, we investigated the lipidomic profiles of long-lived glp-1/notch receptor mutants, which have reproductive deficiency when grown at nonpermissive temperature. The results showed that there was some age-related lipid variation, including TG 40:2, TG 40:1, and TG 41:1, which contributed to the long-life phenotype. The longevity of glp-1 mutant was daf-16-dependent; the lipidome analysis of daf-16;glp-1 double mutant revealed that the changes of some metabolites in the glp-1 mutant were daf-16-dependent, while other metabolites displayed more complex epistatic patterns. We first conducted a comprehensive lipidome analysis to provide novel insights into the relationships between longevity and lipid metabolism regulated by germ line signals in C. elegans.


Assuntos
Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/metabolismo , Lipídeos/análise , Longevidade , Reprodução , Transdução de Sinais , Animais , Caenorhabditis elegans/crescimento & desenvolvimento
5.
Sci Total Environ ; 677: 732-744, 2019 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-31075619

RESUMO

During the past five years, China has witnessed a rapid drop of nitrogen oxides (NOx) owing to the wildly-applied rigorous emission control strategies across the country. However, ozone (O3) pollution was found to steadily deteriorate in most part of eastern China, especially in developed regions such as Jing-Jin-Ji (JJJ), Yangtze River Delta region (YRD) and Pearl River Delta region (PRD). To shed more light on current O3 pollution and its responses to precursor emissions, we integrate satellite retrievals, ground-based measurements together with regional numerical simulation in this study. It is indicated by multiple sets of observational data that NOx in eastern China has declined more than 25% from 2012 to 2016. Based on chemical transport modeling, we find that O3 formation in eastern China has changed from volatile organic compounds (VOCs) sensitive regime to the mixed sensitive regime due to NOx reductions, substantially contributing to the recent increasing trend in urban O3. In addition, such transitions tend to bring about an ~1-1.5 h earlier peak of net O3 formation rate. We further studied the O3 precursors relationships by conducting tens of sensitivity simulations to explore potential ways for effective O3 mitigation. It is suggested that the past control measures that only focused on NOx may not work or even aggravate O3 pollution in the city clusters. In practice, O3 pollution in the three regions is expected to be effectively mitigated only when the reduction ratio of VOCs/NOx is greater than 2:1, indicating VOCs-targeted control is a more practical and feasible way.

6.
Environ Int ; 129: 118-135, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31125731

RESUMO

Can mitigating only particle mass, as the existing air quality measures do, ultimately lead to reduction in ultrafine particles (UFP)? The aim of this study was to provide a broader urban perspective on the relationship between UFP, measured in terms of particle number concentration (PNC) and PM2.5 (mass concentration of particles with aerodynamic diameter < 2.5 µm) and factors that influence their concentrations. Hourly average PNC and PM2.5 were acquired from 10 cities located in North America, Europe, Asia, and Australia over a 12-month period. A pairwise comparison of the mean difference and the Kolmogorov-Smirnov test with the application of bootstrapping were performed for each city. Diurnal and seasonal trends were obtained using a generalized additive model (GAM). The particle number to mass concentration ratios and the Pearson's correlation coefficient were calculated to elucidate the nature of the relationship between these two metrics. Results show that the annual mean concentrations ranged from 8.0 × 103 to 19.5 × 103 particles·cm-3 and from 7.0 to 65.8 µg·m-3 for PNC and PM2.5, respectively, with the data distributions generally skewed to the right, and with a wider spread for PNC. PNC showed a more distinct diurnal trend compared with PM2.5, attributed to the high contributions of UFP from vehicular emissions to PNC. The variation in both PNC and PM2.5 due to seasonality is linked to the cities' geographical location and features. Clustering the cities based on annual median concentrations of both PNC and PM2.5 demonstrated that a high PNC level does not lead to a high PM2.5, and vice versa. The particle number-to-mass ratio (in units of 109 particles·µg-1) ranged from 0.14 to 2.2, >1 for roadside sites and <1 for urban background sites with lower values for more polluted cities. The Pearson's r ranged from 0.09 to 0.64 for the log-transformed data, indicating generally poor linear correlation between PNC and PM2.5. Therefore, PNC and PM2.5 measurements are not representative of each other; and regulating PM2.5 does little to reduce PNC. This highlights the need to establish regulatory approaches and control measures to address the impacts of elevated UFP concentrations, especially in urban areas, considering their potential health risks.


Assuntos
Poluentes Atmosféricos/análise , Material Particulado/análise , Poluição do Ar/análise , Cidades , Tamanho da Partícula , Emissões de Veículos/análise
7.
Proc Natl Acad Sci U S A ; 116(16): 7760-7765, 2019 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-30936298

RESUMO

China has been experiencing fine particle (i.e., aerodynamic diameters ≤ 2.5 µm; PM2.5) pollution and acid rain in recent decades, which exert adverse impacts on human health and the ecosystem. Recently, ammonia (i.e., NH3) emission reduction has been proposed as a strategic option to mitigate haze pollution. However, atmospheric NH3 is also closely bound to nitrogen deposition and acid rain, and comprehensive impacts of NH3 emission control are still poorly understood in China. In this study, by integrating a chemical transport model with a high-resolution NH3 emission inventory, we find that NH3 emission abatement can mitigate PM2.5 pollution and nitrogen deposition but would worsen acid rain in China. Quantitatively, a 50% reduction in NH3 emissions achievable by improving agricultural management, along with a targeted emission reduction (15%) for sulfur dioxide and nitrogen oxides, can alleviate PM2.5 pollution by 11-17% primarily by suppressing ammonium nitrate formation. Meanwhile, nitrogen deposition is estimated to decrease by 34%, with the area exceeding the critical load shrinking from 17% to 9% of China's terrestrial land. Nevertheless, this NH3 reduction would significantly aggravate precipitation acidification, with a decrease of as much as 1.0 unit in rainfall pH and a corresponding substantial increase in areas with heavy acid rain. An economic evaluation demonstrates that the worsened acid rain would partly offset the total economic benefit from improved air quality and less nitrogen deposition. After considering the costs of abatement options, we propose a region-specific strategy for multipollutant controls that will benefit human and ecosystem health.

8.
Sci Total Environ ; 667: 77-85, 2019 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-30826683

RESUMO

In the context of global precipitation anomalies and climate warming, the evolution of fragile desert ecosystems, which account for one-third of the world's land area, will become more complex. Studies of regional climate change and ecosystem response are important components of global climate change research, especially in arid desert regions. Zygophyllum xanthoxylum and Ammopiptanthus mongolicus are two dominant but endangered shrub species in the Alxa Desert in the arid region of central Asia. Using dendrochronological methods, we studied the response of radial growth of those two species to climate factors, and the adaptability of the two shrub populations under a regional warming trend. We found that radial growth of both shrubs was mainly affected by precipitation during the growing season. In additionally, along with the decrease of precipitation and the increase of temperature from east to west of Alxa desert Plateau, the limiting effect of drought during the growing season on radial growth increased. The climate response characteristics and changes between dry and wet periods exhibited spatial and temporal heterogeneity due to micro-level geomorphological factors. Under a regional climate warming trend, individual growth and population development of the two endangered shrubs will be adversely affected. In areas where these species are naturally distributed, populations will gradually become concentrated in micro-geomorphic regions with better soil moisture conditions, such as low-lying areas in the gullies that develop in alluvial fans. This finding has important scientific significance for understanding the development of the region's dominant shrub populations and protection of these and other endangered plants in arid desert areas.


Assuntos
Mudança Climática , Fabaceae/crescimento & desenvolvimento , Zygophyllum/crescimento & desenvolvimento , China , Clima Desértico , Especificidade da Espécie
9.
Ecotoxicol Environ Saf ; 168: 110-119, 2019 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-30384158

RESUMO

Bacteria are ubiquitous in the near-surface atmosphere where they constitute an important component of aerosols with the potential to affect climate change, ecosystems, atmospheric process and human health. Limitation in tracking bacterial diversity accurately has thus far prevented the knowledge of airborne bacteria and their pathogenic properties. We performed a comprehensive assessment of bacterial abundance and diverse community in PM2.5 collected at Mt. Tai, via high-throughput sequencing and real-time PCR. The samples exhibited a high microbial biodiversity and complex chemical composition. The dominating populations were gram-negative bacteria including Burkholderia, Delftia, Bradyrhizobium, and Methylobacterium. The PM mass concentration, chemical composition, bacterial concentration and community structure varied under the influence of different air-mass trajectories. The highest mass concentration of PM2.5 (61 µg m-3) and major chemical components were recorded during periods when marine southeasterly air masses were dominant. The local terrestrial air masses from Shandong peninsula and its adjacent areas harbored highest bacterial concentration loading (602 cells m-3) and more potential pathogens at the site. In contrast, samples influenced by the long-distance air flow from Siberia and Outer Mongolia were found to have a highest richness and diversity as an average, which was also marked by the increase of dust-associated bacteria (Brevibacillus and Staphylococcus). The primary research may serve as an important reference for the environmental microbiologist, health workers, and city planners.


Assuntos
Microbiologia do Ar , Poluentes Atmosféricos/análise , Monitoramento Ambiental , Material Particulado/análise , Administração por Inalação , Aerossóis/análise , Bactérias/classificação , Bactérias/isolamento & purificação , Biodiversidade , China , Análise por Conglomerados , Variações do Número de Cópias de DNA , Poeira/análise , Biblioteca Gênica , Humanos , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
10.
Ecotoxicol Environ Saf ; 166: 146-156, 2018 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-30265878

RESUMO

Aiming to a better understanding sources contributions and regional sources of fine particles, a total of 273 filter samples (159 of PM2.5 and 114 of PM1.0) were collected per 8 h during the winter 2016 at a southwest suburb of Beijing. Chemical compositions, including water soluble ions, organic carbon (OC), and elemental carbon (EC), as well as secondary organic carbon (SOC), were systematically analyzed and estimated. The total ions concentrations (TIC), OC, and SOC of PM2.5 were with the following order: 16:00-24:00 > 08:00-16:00 > 00:00-08:00. Since primary OC and EC were mainly attributed to the residential combustion in the night time, their valley values were observed in the daytime (08:00-16:00). However, the highest ratio value of SOC/OC was observed in the daytime. It is because that SOC is easily formed under sunshine and relatively high temperature in the daytime. Positive matrix factorization (PMF), clustering, and potential source contribution function (PSCF) were employed for apportioning sources contributions and speculating potential sources spatial distributions. The average concentrations of each species and the source contributions to each species were calculated based on the data of species concentrations with an 8 h period simulated by PMF model. Six likely sources, including secondary inorganic aerosols, coal combustion, industrial and traffic emissions, road dust, soil and construction dust, and biomass burning, were contributed to PM2.5 accounting for 29%, 21%, 17%, 16%, 9%, 8%, respectively. The results of cluster analysis indicated that most of air masses were transported from West and Northwest directions to the sampling location during the observation campaign. Several seriously polluted areas that might affect the air quality of Beijing by long-range transport were identified. Most of air masses were transported from Western and Northwestern China. According to the results of PSCF analysis, Western Shandong, Southern Hebei, Northern Henan, Western Inner Mongolia, Northern Shaanxi, and the whole Shanxi provinces should be the key areas of air pollution control in China. The exposure-response function was used to estimate the health impact associated with PM2.5 pollution. The population affected by PM2.5 during haze episodes reached 0.31 million, the premature death cases associated with PM2.5 reached 2032. These results provided important implication for making environmental policies to improve air quality in China.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental , Material Particulado/análise , Medição de Risco , Aerossóis/análise , Aerossóis/química , Poluentes Atmosféricos/química , Poluição do Ar/análise , Pequim , Carbono/análise , Carvão Mineral/análise , Poeira/análise , Poluição Ambiental/análise , Material Particulado/química , Estações do Ano , Solo , Emissões de Veículos/análise
11.
Sci Adv ; 4(3): eaap7314, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29750188

RESUMO

Polycyclic aromatic hydrocarbons like benzo(a)pyrene (BaP) in atmospheric particulate matter pose a threat to human health because of their high carcinogenicity. In the atmosphere, BaP is mainly degraded through a multiphase reaction with ozone, but the fate and atmospheric transport of BaP are poorly characterized. Earlier modeling studies used reaction rate coefficients determined in laboratory experiments at room temperature, which may overestimate/underestimate degradation rates when applied under atmospheric conditions. Moreover, the effects of diffusion on the particle bulk are not well constrained, leading to large discrepancies between model results and observations. We show how regional and global distributions and transport of BaP can be explained by a new kinetic scheme that provides a realistic description of the temperature and humidity dependence of phase state, diffusivity, and reactivity of BaP-containing particles. Low temperature and humidity can substantially increase the lifetime of BaP and enhance its atmospheric dispersion through both the planetary boundary layer and the free troposphere. The new scheme greatly improves the performance of multiscale models, leading to better agreement with observed BaP concentrations in both source regions and remote regions (Arctic), which cannot be achieved by less-elaborate degradation schemes (deviations by multiple orders of magnitude). Our results highlight the importance of considering temperature and humidity effects on both the phase state of aerosol particles and the chemical reactivity of particulate air pollutants.

12.
Sci Total Environ ; 633: 1007-1011, 2018 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-29758853

RESUMO

Fireworks have been identified as one ozone source by photolyzing NO2 or O2 and are believed to potentially be important for the nighttime ozone during firework events. In this study, we conducted both lab and field experiments to test two types of fireworks with low and high energy with the goal to distinguish whether the visible ozone signal during firework displays is real. The results suggest that previous understanding of the ozone formation mechanism during fireworks is misunderstood. Ultraviolet ray (UV)-based ozone monitors are interfered by aerosols and some specific VOCs. High-energy fireworks emit high concentrations of particular matters and low VOCs that the artificial ozone can be easily removed by an aerosol filter. Low-energy fireworks emit large amounts of VOCs mostly from the combustion of the cardboard from fireworks that largely interferes with the ozone monitor. Benzene and phenol might be major contributors to the artificial ozone signal. We further checked the nighttime ozone concentration in Jinan and Beijing, China, during Chinese New Year, a period with intense fireworks. A signal of 3-8ppbv ozone was detected and positively correlated to NO and SO2, suggesting a considerable influence of these chemicals in interfering with ambient ozone monitoring.

13.
Crit Care ; 21(1): 188, 2017 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-28709443

RESUMO

BACKGROUND: In 2012, the European Society of Intensive Care Medicine proposed a definition for acute gastrointestinal injury (AGI) based on current medical evidence and expert opinion. The aim of the present study was to evaluate the feasibility of using the current AGI grading system and to investigate the association between AGI severity grades with clinical outcome in critically ill patients. METHODS: Adult patients at 14 general intensive care units (ICUs) with an expected ICU stay ≥24 h were prospectively studied. The AGI grade was assessed daily on the basis of gastrointestinal (GI) symptoms, intra-abdominal pressures, and feeding intolerance (FI) in the first week of admission to the ICU. RESULTS: Among the 550 patients enrolled, 456 patients (82.9%) received mechanical ventilation, and 470 patients were identified for AGI. The distribution of the global AGI grade was 24.5% with grade I, 49.4% with grade II, 20.6% with grade III, and 5.5% with grade IV. AGI grading was positively correlated with 28- and 60-day mortality (P < 0.0001). Univariate Cox regression analysis showed that age, sepsis, diabetes mellitus, coronary artery disease, the use of vasoactive drugs, serum creatinine and lactate levels, mechanical ventilation, Acute Physiology and Chronic Health Evaluation II (APACHE II) score, and the global AGI grade were significantly (P ≤ 0.02) associated with 60-day mortality. In a multivariate analysis including these variables, diabetes mellitus (HR 1.43, 95% CI 1.03-1.87; P = 0.05), the use of vasoactive drugs (HR 1.56, 95% CI 1.12-2.11; P = 0.01), serum lactate (HR 1.15, 95% CI 1.06-1.24; P = 0.03), global AGI grade (HR 1.65, 95% CI 1.28-2.12; P = 0.008), and APACHE II score (HR 1.04, 95% CI 1.02-1.06; P < 0.001) were independently associated with 60-day mortality. In a subgroup analysis of 402 patients with 7-day survival, in addition to clinical predictors and the AGI grade on the first day of ICU stay, FI within the first week of ICU stay had an independent and incremental prognostic value for 60-day mortality (χ2 = 41.9 vs. 52.2, P = 0.007). CONCLUSIONS: The AGI grading scheme is useful for identifying the severity of GI dysfunction and could be used as a predictor of impaired outcomes. In addition, these results support the hypothesis that persistent FI within the first week of ICU stay is an independent determinant for mortality. TRIAL REGISTRATION: Chinese Clinical Trial Registry identifier: ChiCTR-OCS-13003824 . Registered on 29 September 2013.


Assuntos
Traumatismos Abdominais/mortalidade , Gastroenteropatias/mortalidade , APACHE , Traumatismos Abdominais/epidemiologia , Idoso , Idoso de 80 Anos ou mais , Estado Terminal/epidemiologia , Estado Terminal/mortalidade , Feminino , Gastroenteropatias/epidemiologia , Humanos , Unidades de Terapia Intensiva/organização & administração , Unidades de Terapia Intensiva/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade , Prognóstico , Modelos de Riscos Proporcionais , Estudos Prospectivos , Análise de Regressão , Índice de Gravidade de Doença
14.
Nat Prod Bioprospect ; 7(5): 335-404, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28567542

RESUMO

Aging is a process characterized by accumulating degenerative damages, resulting in the death of an organism ultimately. The main goal of aging research is to develop therapies that delay age-related diseases in human. Since signaling pathways in aging of Caenorhabditis elegans (C. elegans), fruit flies and mice are evolutionarily conserved, compounds extending lifespan of them by intervening pathways of aging may be useful in treating age-related diseases in human. Natural products have special resource advantage and with few side effect. Recently, many compounds or extracts from natural products slowing aging and extending lifespan have been reported. Here we summarized these compounds or extracts and their mechanisms in increasing longevity of C. elegans or other species, and the prospect in developing anti-aging medicine from natural products.

15.
Sci Rep ; 7: 44224, 2017 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-28287139

RESUMO

China is one of the most heavily polluted nations and is also the largest agricultural producer. There are relatively few studies measuring the effects of pollution on crop yields in China, and most are based on experiments or simulation methods. We use observational data to study the impact of increased air pollution (surface ozone) on rice yields in Southeast China. We examine nonlinearities in the relationship between rice yields and ozone concentrations and find that an additional day with a maximum ozone concentration greater than 120 ppb is associated with a yield loss of 1.12% ± 0.83% relative to a day with maximum ozone concentration less than 60 ppb. We find that increases in mean ozone concentrations, SUM60, and AOT40 during panicle formation are associated with statistically significant yield losses, whereas such increases before and after panicle formation are not. We conclude that heightened surface ozone levels will potentially lead to reductions in rice yields that are large enough to have implications for the global rice market.


Assuntos
Produtos Agrícolas/crescimento & desenvolvimento , Oryza/crescimento & desenvolvimento , Ozônio/análise , Ozônio/metabolismo
16.
Nat Prod Bioprospect ; 7(2): 207-214, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28194725

RESUMO

Alzheimer's disease (AD) is a major public health concern worldwide and the few drugs currently available only treat the symptoms. Hence, there is a strong need to find more effective anti-AD agents. Cynanchum otophyllum is a traditional Chinese medicine for treating epilepsy, and otophylloside B (Ot B), isolated from C. otophyllum, is the essential active component. Having previously identified anti-aging effects of Ot B, we evaluated Ot B for AD prevention in C. elegans models of AD and found that Ot B extended lifespan, increased heat stress-resistance, delayed body paralysis, and increased the chemotaxis response. Collectively, these results indicated that Ot B protects against Aß toxicity. Further mechanistic studies revealed that Ot B decreased Aß deposition by decreasing the expression of Aß at the mRNA level. Genetic analyses showed that Ot B mediated its effects by increasing the activity of heat shock transcription factor (HSF) by upregulating the expression of hsf-1 and its target genes, hsp-12.6, hsp-16.2 and hsp-70. Ot B also increased the expression of sod-3 by partially activating DAF-16, while SKN-1 was not essential in Ot B-mediated protection against Aß toxicity.

17.
Aging (Albany NY) ; 9(2): 447-474, 2017 02 06.
Artigo em Inglês | MEDLINE | ID: mdl-28177875

RESUMO

In Caenorhabditis elegans (C. elegans), ablation of germline stem cells (GSCs) leads to infertility, which extends lifespan. It has been reported that aging and reproduction are both inextricably associated with metabolism. However, few studies have investigated the roles of polar small molecules metabolism in regulating longevity by reproduction. In this work, we combined the nuclear magnetic resonance (NMR) and ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) to profile the water-soluble metabolome in C. elegans. Comparing the metabolic fingerprint between two physiological ages among different mutants, our results demonstrate that aging is characterized by metabolome remodeling and metabolic decline. In addition, by analyzing the metabolic profiles of long-lived germline-less glp-1 mutants, we discovered that glp-1 mutants regulate the levels of many age-variant metabolites to attenuate aging, including elevated concentrations of the pyrimidine and purine metabolism intermediates and decreased concentrations of the citric acid cycle intermediates. Interestingly, by analyzing the metabolome of daf-16;glp-1 double mutants, our results revealed that some metabolic exchange contributing to germline-mediated longevity was mediated by transcription factor FOXO/DAF-16, including pyrimidine metabolism and the TCA cycle. Based on a comprehensive metabolic analysis, we provide novel insight into the relationship between longevity and metabolism regulated by germline signals in C. elegans.


Assuntos
Envelhecimento/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/metabolismo , Longevidade/fisiologia , Receptores Notch/metabolismo , Envelhecimento/genética , Animais , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/genética , Regulação da Expressão Gênica , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Metabolômica , Receptores Notch/genética
18.
Sci Total Environ ; 584-585: 426-447, 2017 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-28126285

RESUMO

China is one of the regions with highest PM2.5 concentration in the world. In this study, we review the spatio-temporal distribution of PM2.5 mass concentration and components in China and the effect of control measures on PM2.5 concentrations. Annual averaged PM2.5 concentrations in Central-Eastern China reached over 100µgm-3, in some regions even over 150µgm-3. In 2013, only 4.1% of the cities attained the annual average standard of 35µgm-3. Aitken mode particles tend to dominate the total particle number concentration. Depending on the location and time of the year, new particle formation (NPF) has been observed to take place between about 10 and 60% of the days. In most locations, NPF was less frequent at high PM mass loadings. The secondary inorganic particles (i.e., sulfate, nitrate and ammonium) ranked the highest fraction among the PM2.5 species, followed by organic matters (OM), crustal species and element carbon (EC), which accounted for 6-50%, 15-51%, 5-41% and 2-12% of PM2.5, respectively. In response to serious particulate matter pollution, China has taken aggressive steps to improve air quality in the last decade. As a result, the national emissions of primary PM2.5, sulfur dioxide (SO2), and nitrogen oxides (NOX) have been decreasing since 2005, 2006, and 2011, respectively. The emission control policies implemented in the last decade could result in noticeable reduction in PM2.5 concentrations, contributing to the decreasing PM2.5 trends observed in Beijing, Shanghai, and Guangzhou. However, the control policies issued before 2010 are insufficient to improve PM2.5 air quality notably in future. An optimal mix of energy-saving and end-of-pipe control measures should be implemented, more ambitious control policies for NMVOC and NH3 should be enforced, and special control measures in winter should be applied. 40-70% emissions should be cut off to attain PM2.5 standard.

19.
J Proteomics ; 156: 85-93, 2017 03 06.
Artigo em Inglês | MEDLINE | ID: mdl-28119113

RESUMO

The abrogation of the germ cells in Caenorhabditis elegans (C. elegans) by either genetic means or cell ablation results in about 60% increase of longevity. Upon the inhibition of germline stem cell proliferation, certain signaling molecules inhibit the target of rapamycin (TOR), activate the transcription factors including DAF-16, DAF-12, and PHA-4, leading to altered fatty acid lipolysis, autophagy, stress resistance, and the extended lifespan. But the exact cascades and interactions of those signaling pathways are still obscure. To understand how the reproductive system affects aging at the protein level, we determined the protein expression profile of the long-lived temperature-sensitive mutant glp-1(e2141) and wild-type N2 using isobaric tags for relative and absolute quantitation (iTRAQ) technology. Our results showed that the abundance of proteins relevant to transcription, RNA processing, translation, protein folding, and proteolytic process were decreased, while collagen proteins and proteins involved in detoxification and innate immune responses were increased in C. elegans glp-1 mutant, these alterations of protein abundance might attenuate protein metabolism and enhance immune response and stress resistance, and finally contribute to germline-mediated longevity. BIOLOGICAL SIGNIFICANCE: This study provides an overview of the altered protein expression upon germline ablation. Germ-cell loss results in decreased abundance of proteins involved in protein synthesis and breakdown, and increased abundance of proteins involved in detoxification and immune response, suggesting that protein synthesis and metabolism might be attenuated, while detoxification and immune responses might be increased. The altered protein abundance might result in physiological adaptations that contribute to extended longevity in germline-deficient C. elegans. This study brings new light on the role of reproductive control of lifespan.


Assuntos
Caenorhabditis elegans/química , Células Germinativas/citologia , Proteômica/métodos , Envelhecimento , Animais , Proteínas de Caenorhabditis elegans/análise , Regulação da Expressão Gênica no Desenvolvimento , Imunidade , Inativação Metabólica , Longevidade , Transdução de Sinais
20.
J Gerontol A Biol Sci Med Sci ; 72(4): 464-472, 2017 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-27378235

RESUMO

Coffee and tea, two of the most popular drinks around the world, share many in common from chemical components to beneficial effects on human health. One of their shared components, the polyphenols, most notably chlorogenic acid (CGA), was supposed to account for many of the beneficial effects on ameliorating diseases occurred accompanying people aging, such as the antioxidant effect and against diabetes and cardiovascular disease. CGA is also present in many traditional Chinese medicines. However, the mechanism of these effects was vague. The aging signaling pathways were conservative from yeast and worms to mammals. So, we tested if CGA had an effect on aging in Caenorhabditis elegans. We found that CGA could extend the lifespan of C. elegans by up to 20.1%, delay the age-related decline of body movement, and improve stress resistance. We conducted genetic analysis with a series of worm mutants and found that CGA could extend the lifespan of the mutants of eat-2, glp-1, and isp-1, but not of daf-2, pdk-1, akt-1, akt-2, sgk-1, and clk-1. CGA could activate the FOXO transcription factors DAF-16, HSF-1, SKN-1, and HIF-1, but not SIR-2.1. Taken together, CGA might extend the lifespan of C. elegans mainly via DAF-16 in insulin/IGF-1 signaling pathway.


Assuntos
Caenorhabditis elegans/efeitos dos fármacos , Caenorhabditis elegans/fisiologia , Ácido Clorogênico/farmacologia , Fator de Crescimento Insulin-Like I/efeitos dos fármacos , Fator de Crescimento Insulin-Like I/fisiologia , Insulina/fisiologia , Longevidade/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Animais
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